1. Field of the Invention
This application relates to the field of computer casings and more particularly to a hinge unit of a portable computer which reduces the number of components and consequently in reduced manufacturing cost and improved abrasion resistance.
2. Description of the Related Art
In general, a display unit of a portable computer is coupled to a computer main body by a hinge unit. An example of this hinge unit of the portable computer is disclosed in Japanese Patent First Publication No. 2003-161311.
As shown in FIGS. 1 and 2, (which are comparable to FIGS. 2 and 3 of the aforementioned '311 application) a hinge unit 1 includes a hinge pivot 10, a first connecting body 20 coupled to a display unit, a second connecting body 30 coupled to a computer main body unit, a pair of a first cam member 40 and second cam member 50 coupled respectively to the first connecting body 20 and the second connecting body 30 and having inclination surfaces 45 and 55 (see FIG. 2) formed on facing surfaces of cam members 40, 50, respectively. Also illustrated is a spring 50 pressing the first cam member 40 to the second cam member 50 along an axially direction of the hinge pivot 10, etc. The first cam member 40 and the second cam member 50 are locked to and withdrawn from each other depending on a relative rotation of surfaces 45 and 55
However, since the inclination surfaces 45 and 55 of the first cam member 40 and the second cam member 50 of the conventional hinge unit 1 for a portable computer contact in the axis direction of the hinge pivot 10 and receive the pressing force of the spring 60 in a vertical direction, the friction force is seriously applied depending on the relative rotation to easily cause abrasion. Also, since components configuring the hinge unit 1 are many, the manufacturing cost increases.